Microscope drape and method of making same

ABSTRACT

A microscope drape fabricated from a thin soft, relatively inexpensive, plastic film which will melt at temperatures considerably lower than the temperatures which are developed by the illuminating lamp of an operating microscope, is provided with a heat barrier loosely secured to and carried by the inner surface of that portion of the film which, but for the presence of the barrier would be adversely affected by the temperatures induced within the drape adjacent the illuminating lamp of the drape-enshrouded microscope.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention relates to sterilized disposable drapes forenshrouding operating microscopes and their support arms.

2. Description of the Prior Art

U.S. Pat. No. 3,698,791 of D. L. Walchle, et al, discloses a microscopedrape which is fabricated from a thin, transparent, relatively expensivesterilizable copolymer film which is capable of withstanding thetemperatures induced by the illuminating lamp of an operatingmicroscope, said drape being adapted to completely house an operatingmicroscope including its support arm, whereby heated air cannot escapefrom the interior of the drape except through the open end thereof whichis located remote from the microscope and the operating zone.

U.S. Pat. No. 3,528,720, of H. T. Treace discloses a microscope drapewhich is fabricated from thin, sterilizable, flexible sheet materialwhich is adversely affected by the temperatures developed by theilluminating lamp of an operating microscope. The drape includes exhaustport means 77 in the upper portion of the drape through which heated airfrom the interior of the drape is exhausted upwardly of the microscopedirectly into the operating zone. The said exhaust port is fitted with adisk-like mass 85 of open-cell foam-plastic material which permits afree outward flow of heated air from the interior of the microscopedrape and provides baffle or screen means for excluding dust and foreignmatter from the interior of the envelope from escaping into the room.The open-cell foam plastic material 85 also provides a surface againstwhich the operating instruments may be wiped to quickly clean same. Theexhaust of heated air outwardly through said open-cell material willdistribute whatever spores, germs or the like are wiped onto its outersurface directly into the operating zone.

U.S. Pat. No. 3,542,450 of W. I. Terhune discloses a metallic U-shapedheat baffle 11 which is secured to the head assembly of an operatingmicroscope adjacent the lamp housing thereof for preventing a drapefabricated from thin film from contacting the lamp housing or otherlamp-heated portions of the microscope. The inner surface of theU-shaped baffle is preferably coated with insulating means in the formof thick foam plastic material 69 69' and 71 adhesively secured thereto.A microscope-encompassing drape is provided with an open, non-obstructedexhaust port grommet 49 in the upper portion thereof for exhaustingheated air from the interior of the drape directly into the operatingzone of the operating room, immediately above the operating microscope.

U.S. Pat. No. 3,796,477 of J. L. Geraci discloses a microscope drapewhich is fabricated from thin, transparent sterilizable film, similar tothat of U.S. Pat. No. 3,698,791 supra, wherein the drape includes aflexible, resilient, distortable lens housing which is adapted to snuglyreceive the objective lens ring of the objective lens of an operatingmicroscope.

U.S. Pat. No. 4,045,118 of J. L. Geraci discloses a microscope drapefabricated from a very thin, transparent, heat resistant, sterilizableplastic film which is adapted to completely house an operatingmicroscope including its support arms wherein the drape is provided withunique tubular ocular housing extensions 40 the free outer ends of whichterminate in a pull tab which serves to facilitate precise positioningof the tubular housings on the ocular of a microscope and to facilitateremoval of said pull tabs which, prior to removal, accurately andeffectively position the free outer end of the ocular housing extensionsremaining after removal of the tab portion closely adjacent to the outerends of the eye-pieces of the oculars of the microscope.

U.S. Pat. Nos. 3,698,791; 3,796,477 and 4,045,118 are owned by theassignee of the present application.

SUMMARY OF THE INVENTION

The microscope drape of the present invention is directed to acompletely sterile housing in the form of an elongate tubular portionwithin which an unsterile operating microscope and its horizontalsupport arms are completely housed in such a manner as to positivelypreclude the exhaust of heated air into the operating room at a locationadjacent the operating zone in the immediate vicinity of the microscope.Those of the prior art microscope drapes which were fabricated fromthin, flexible polyethylene material were softer and quiet, in the sensethat they did not crinkle when brushed against nor did they produce aglare since the surface thereof was not shiny. However since the filmdid melt at temperatures in the neighborhood of 100° F. belowtemperatures produced by the light source of a microscope such drapescould not be used unless special means and precautions were taken toensure that the drape material was, at all times maintained insufficiently spaced relationship with respect to the light-source of amicroscope as to prevent damage to the drape.

Drapes fabricated from polypropylene film which is capable ofwithstanding the temperatures induced by the light-source of anoperating microscope did not possess the advantages of softness,quietness and lack of glare as possessed by drapes fabricated frompolyethylene, and the polypropylene drapes were considerably moreexpensive than the polyethylene drapes.

The primary object of the subject invention is to provide a heat barrierdissipator in the form of a sheet of foam material which is looselysecured to the inner surface of the drape material whereby to bedisposed between the drape material and the light source of a separatemicroscope.

The effect of the protective sheet is to absorb and dissipate the heatgenerated by the lamp whereby the temperature of the film in the area ofthe source of light is maintained at a temperature which issubstantially below its melting temperature.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a typical arm-supported microscope housedwithin a drape of the present invention.

FIG. 2 is a plan view of the drape prior to being associated with amicroscope and its support arm.

FIG. 3 is a side view of the microscope wherein the drape and its heatbarrier sheet are illustrated in section.

FIG. 4 is a view taken on line 4--4 of FIG. 3.

PREFERRED EMBODIMENT OF THE INVENTION

In FIGS. 1 and 3 a conventional operating microscope has beenillustrated as encapsulated within a, sterilized, soft, flexible drape Dof the subject invention.

The microscope is, as best illustrated in FIG. 1 of U.S. Pat. No.3,698,791 mounted relative to an upright or other member by means of asupport arm which may comprise a series of adjustably interconnectedelements (as illustrated in said patent) which are articulated in such amanner as to enable the user of the microscope to adjust it in anydesired position for enabling an observer looking into eyepiece 36 ofoculars 38 to examine and study various portions of a patient to betreated and/or operated on, such as, by way of example, the eyes, ears,nose, throat, etc. The microscope includes an objective lens and anilluminating lamp, not illustrated, which is housed within an open-tophousing 10 for providing a high intensity source of light for themicroscope. The present invention is neither concerned with nor directedto the particular structural details of the operating microscope, sincesuch devices are commercially available as standard articles ofcommerce.

In FIG. 1 the numerals 28, 30 and 32 denote generally a portion of theadjustably connected elements which comprise a portion of the supportarm by which the operating microscope is articulated relative to arm 28of FIG. 1 of reference U.S. Pat. No. 3,698,791.

In FIG. 2 the drape of the present invention is illustrated in a flat,fully extended position as it would appear when ready to be folded intoa compact package such as, by way of example, is illustrated in FIG. 2of the aforesaid reference patent.

In the preferred embodiment of the invention the drape D is fabricatedfrom soft, inexpensive, flexible, sterilizable non-glare polyethylenefilm approximately 2 mil thick which has a melting point in theneighborhood of 240° F. which is considerably lower than thetemperatures developed within the drape and adjacent the illuminatinglamp of the microscope.

A heat shield or barrier 12 is loosely secured to the inner surface ofthat portion of the film of the drape which, but for the presence ofsaid heat shield or barrier, would be adversely affected by thetemperatures developed interiorly of the drape adjacent the illuminatinglamp. The heat shield or barrier 12, may by way of example, be securedalong two of its opposed side edges such as, by means of double-facedadhesive strips 20 whereby those portions of the shield between theattachment strips is disposed in loose, overlying relationship and freeof connection to the drape whereby a certain amount of relative movementbetween the shield and drape may occur incident to manufacture,packaging, shipment, storage and actual use of the drape. Uniformlysatisfactory results have been obtained in those instances in which theheat shield or barrier 12 comprises a sheet of open-cell polypropylenefoam which is not adversely affected by the temperatures induced withinthe drape by and adjacent the illuminating lamp of the microscope.

It is believed that the open-cells of the polypropolene sheet permitsthe highly heated air within the drape, adjacent the illuminating lampto pass through foam which functions as a heat-sink to effectivelyreduce the temperature of the air within the drape adjacent theilluminating lamp to temperatures which will not adversely affect thepolyethylene film of the drape.

It will be understood that the heated air from the interior of the drapeis positively precluded from being discharged into the operating zoneadjacent the operating microscope, or into the operating zone, since thedrape, when in use, as illustrated in FIG. 1 of U.S. Pat. No. 3,698,791is open to the atmosphere, only at its open end which is disposedadjacent the means such as upright 22 of the aforesaid reference patentto which the support arm 28 is mounted.

The subject drape combines the soft, flexible, sterilizable,inexpensive, non-glare characteristics of thin polyethylene film, whichis adversely affected by the temperatures induced by the illuminatinglamp of an operating microscope with the temperature-resistingcharacteristics of the sheet of open-cell, sterilizable, flexible heatshield or barrier which is not adversely affected by the heat within thedrape as developed adjacent and by the illumination lamp of themicroscope. The resultant drape has all of the advantages with none ofthe disadvantages of a drape fabricated entirely from thin polyethylenefilm.

The subject drape, for the first time, enables drapes for operatingmicroscopes to be fabricated from thin, soft, flexible polyethylene filmwhereby the heated air is discharged through the open end of the drapeat a location remote from the operating microscope, wherein the film ofsaid drape is rendered resistant to or protected from those temperaturesadjacent the illumination lamp which would otherwise adversely affectit, by means of a comparatively small sheet of open-cell polypropylenefoam approximately 1/8 inch thick.

In FIG. 1 the letter L designates, generally a lens housing of U.S. Pat.No. 3,796,477. In FIG. 2 the numerals 21 designate generally a pair ofcylindrical drape extensions which are dimensioned to telescopicallyengage the oculars 38 of a microscope after which they are tightlysecured against and relative to the outer surface of the oculars wherebyto preclude the exhaust of heated air from the interior of the drapefrom around the oculars.

Reference is made to FIGS. 6 through 12 of reference U.S. Pat. No.3,698,791 for a detailed description of the manner in which the drape ofthe present invention is secured in enveloping relationship with respectto an operating microscope and its support arms.

Excellent results have been obtained in those instances in which theheat barrier 12 comprises a sheet of 12" by 12" 1/8" open-cellpolypropylene foam 1/8" thick as sold by Sur-Seal Gasket Co. ofCincinnati, Ohio.

With particular reference now to FIG. 2 it will be noted that lenshousing L is secured to and carried by that portion of the drape whichdefines the lower portion 14 when associated with a microscope, whereasthe heat baffle sheet 12 is attached to the inner surface 16 of theupper portion 18 of the drape at and adjacent that portion of the filmwhich overlies and/or is adjacent the illumination lamp of themicroscope, within housing 10.

The resultant drape has all of the advantages and none of thedisadvantages of a polyethylene film drape.

What is claimed is:
 1. In a disposable drape for positioning over anoperating microscope and its support arm wherein the drape is fabricatedfrom a thin, flexible, air-impervious film which is adversely affectedby the temperatures induced within the drape adjacent the source ofillumination of the microscope, the improvement which comprises;a sheetof flexible material, characterized by its porous open-cell structureand its ability to withstand the temperatures induced within the drapeadjacent the source of illumination of the microscope, positioned inloose contacting relationship against the inner surface of the drapewhereby to provide a heat barrier which shields the drape adjacent saidsource of illumination from attaining temperatures sufficiently high toadversely affect the drape material.
 2. A drape as called for in claim1, wherein the drape is fabricated from polyethylene film and the saidsheet comprises open-cell polypropylene foam.
 3. A drape as called forin claim 2, wherein the film of the drape is approximately 2 mil thick,and the said sheet is approximately 1/8" thick.
 4. A drape as called forin claim 1, wherein the said sheet is substantially rectangular in shapeand wherein the said sheet is fastened to a localized area of the innersurface of the film along two of its opposed side edges whereby allother portions of the sheet are disposed in loose, abutting relationshipwith respect to the inner surface of the film.
 5. A drape as called forin claim 4, wherein the said sheet is secured to the film by doublefaced adhesive strips.
 6. The method of preventing a localized area ofthe thin, flexible film of a microscope drape from melting or beingotherwise adversely affected by close proximity toillumination-lamp-induced temperatures in excess of the meltingtemperature of the film when the drape is disposed in envelopingrelationship with an operating microscope, which comprises the step ofpositioning a sheet of open-cell material which is capable ofwithstanding the said illumination-lamp-induced temperatures inoverlying relationship with that surface of the area of the film whichis adjacent the source of the illumination-lamp-induced temperatures. 7.The method as called for in claim 1, wherein substantially the entirearea of the sheet is free of direct attachment to the film.
 8. Themethod as called for in claim 1, wherein the film is polyethylene. 9.The method as called for in claim 8, wherein the thickness of the filmapproximates 2 mils.
 10. The method as called for in claim 1, whereinthe sheet of open-cell foam material is polypropylene.
 11. The method ascalled for in claim 10, wherein the thickness of the sheet approximates1/8".
 12. The method as called for in claim 1, wherein the sheet isadhesively secured to the said localized area of the film at locationsadjacent the peripheral edges of the sheet, and wherein all otherportions of the sheet are in overlying relationship with, but free ofattachment to the film.